1. Field of the Invention
The present invention relates to a backlight unit and a liquid crystal display (LCD) device including the same.
2. Discussion of the Related Art
Recently, flat panel display devices that can decrease a weight and a volume corresponding to the limitations of Cathode Ray Tubes (CRTs) are being developed. Liquid Crystal Display (LCD) devices, Plasma Display Panels (PDPs), Field Emission Display (FED) devices, and light emitting display devices are actively being researched as flat type display devices. However, among such flat panel display devices, LCD devices are easily manufactured, have good drivability of drivers, realize a high-quality image, and thus are attracting much attention.
LCD devices display a moving image by using thin film transistors (TFTs) as switching elements. LCD devices are used as display devices for notebook computers, tablet computers, navigations, or various portable information devices, in addition to televisions or monitors.
Since LCD devices are not self-emitting devices, a backlight unit is prepared under a liquid crystal display panel, and the LCD devices display an image by using light emitted from the backlight unit.
A light emitting diode (LED) is attracting much attention as a light source of the backlight unit. The LED is eco-friendly because having a good energy-saving effect and has a high response time, and thus are attracting much attention as a next-generation light source.
General backlight units are categorized into edge-type backlight units, in which one or more light sources are disposed to face at least one side surface of a light guide plate, and direct-type backlight units in which a plurality of light sources are disposed under a diffusive plate. Recently, the edge-type backlight units are mainly used with the sliming trend of LCD devices.
The edge-type backlight units use a light guide plate for traveling light, emitted from a light source, to a liquid crystal display panel, but a defect is caused by the thermal deformation and movement of the light guide plate. In an LCD device disclosed in Korean Patent Publication No. 10-2012-0026675 (hereinafter referred to as a reference document), a plurality of guide grooves are formed in an edge of a light guide plate, and a boss is formed in a cover bottom corresponding to the guide grooves, thereby preventing the thermal deformation and movement of the light guide plate by using the boss and the guide grooves.
However, the LCD device disclosed in the reference document has the following limitations.
First, non-uniform luminance occurs due to the light reflection of the guide grooves formed in the light guide plate.
Second, the boss is broken by the thermal deformation of the light guide plate.
Third, the size of the light guide plate is enlarged by the guide grooves of the light guide plate, causing the increase in the Bezel width of the LCD device.